Under Ligntning Builder CSS 

[![enter image description here][1]][1]

```css
/*Inline Radio Buttons*/
.radio-combo-inline .slds-form-element__control .slds-radio
{
    display: inline-block !important;
}
```    
Add Above And Final use in HTML be looklike 
```html
<lightning-radio-group name="radioGroup"
                       label="Sort By"
    				   options={sortBySelectionValues}
    				   value={value}
    				   class="radio-combo-inline"
    				   type="radio"></lightning-radio-group>
```

[1]: https://i.sstatic.net/6K0kl.png